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 Mobile ViewMOLD: A COMPLETE GUIDE to TEST CLEAN PREVENT AIR CLEANER PURIFIER TYPES AIR FILTERS for HVAC SYSTEMS AIR POLLUTANTS, COMMON INDOOR AIR QUALITY IMPROVEMENT STRATEGIES ALLERGEN TESTS for BUILDINGS ANIMAL ALLERGENS / PET DANDER ANIMAL ODORS IN BUILDINGSS ATTORNEYS and EXPERT WITNESSES BASEMENT MOLD BATHROOM MOLD BIBLIOGAPHY ENVIRONMENTAL HEALTH, MOLD, IAQ BIOLOGICAL POLLUTANTS CAR MOLD CONTAMINATION CARPET DUST IDENTIFICATION CARPET MOLD CONTAMINATION CAT DANDER in BUILDINGS COMBUSTION GASES & PARTICLE HAZARDS CONDENSATION or SWEATING PIPES, TANKS CPSC Indoor Air Pollution Book Online Copy DUCT SYSTEM & DUCT DEFECTS EMERGENCY RESPONSE, IAQ, GAS, MOLD FIBERGLASS HAZARDS FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP FLOODS IN BUILDINGS-mold FORMALDEHYDE HAZARDS GAS EXPOSURE EFFECTS, TOXIC HUMIDITY CONTROL & TARGETS INDOORS HOUSE DUST ANALYSIS INDOOR AIR QUALITY IMPROVEMENT GUIDE INSULATION MOLD MILDEW REMOVAL & PREVENTION MOISTURE CONTROL in BUILDINGS MOLD GROWTH on SURFACES, TABLE OF MYCOPHOBIA, STAINS MISTAKEN for MOLD NOISE / SOUND DIAGNOSIS & CURE ODORS GASES SMELLS, DIAGNOSIS & CURES OZONE HAZARDS OZONE for MOLD OR ODORS RADON HAZARD TESTS & MITIGATION SAFETY HAZARDS GUIDE SICK HOUSE IAQ QUESTIONNAIRE SMELL PATCH TEST to Track Down Odors STAIN DIAGNOSIS on BUILDING INTERIORS VENTILATION in BUILDINGS More Information |
Guide to vacuuming building cavities to screen for particles, dust, or mold: this article explains the advantages and shortcomings of using vacuum cassettes or spore traps to collect mold test samples (or other dust or particle samples) from building wall and ceiling cavities. In this article series discuss the validity of nearly all of the popular mold testing methods currently in use, pointing out the strengths and weakness of each approach to mold sampling in the indoor environment, beginning with air sampling for airborne mold levels indoors. Because mold test validity and mold test accuracy are often confused, readers should also see ACCURACY OF VARIOUS MOLD TEST METHODS. People who need to conduct mold inspection and testing indoors should see MOLD TEST PROCEDURES and TECHNICAL & LAB PROCEDURES. Green links show where you are. © Copyright 2013 InspectAPedia.com, All Rights Reserved. Author Daniel Friedman. Validity/Accuracy of Vacuuming Building Cavities for a Hidden Mold Screen
Vacuuming building cavities is a popular screening practice to look for mold reservoirs. The investigator is trying to explore wall cavities while doing minimal or no visible damage. A wall-check™ system has been marketed for this purpose and several manufacturers have coped the basic idea: a receiving Air-o-Cel™ or MCE filter cassette is attached at its inlet side to a tube which is inserted as a probe into a wall cavity, permitting creation of only a small hole. The outlet or pump side of the test device is connected to a pump and operated, typically at 15 lpm. Where we have tested this method we have experimented with both passive collection (what most investigators use) or aggressive collection (banging on the wall/ceiling at various points to attempt to dislodge and stir particles). Short duration samples, 1-2 minutes using an Air-o-Cell ™ permit a comparatively large number of samples to be collected in a reasonably short interval. Long duration samples, perhaps for up to two hours, are collected using an MCE filter cassette. Our MOLD INFORMATION CENTER includes more broad discussions of the overall approach to building investigation, as do many expert references cited at that web. For a more comprehensive collection information about mold test methods see INDOOR AIR QUALITY METHODS COMPARED. For more on "mold classes" (Cosmetic mold vs. allergenic mold vs. toxic or pathogenic mold) see MOLD CLASSES, HAZARD LEVELS Wall Cavity Vacuuming - Found IneffectiveWorking with Louis Relle, a Louisiana mold remediation expert on a New
Orleans Building which was to be demolished we collected wall-check samples from every suspect Building cavity. Shortcomings of vacuuming building cavities through a tube but our testing strongly suggests that this method is very unreliable for characterizing wall contents. We do not believe that enough air movement is created in the wall cavity (sucking any lpm flow through a small diameter tube) to reliably collect what could be a severe mold reservoir that happens not to be right next to the probe. Further if the cavity is insulated there will be virtually no air or particle movement except from very close to the probe. What should we make of wall vacuum test results done without other inspection and testing?
Our photo, left, is not showing the wall-check vacuum method that relies on vacuuming into a cassette through a hole in the wall. Instead, here we have pulled loose paneling and have inserted our spore trap cassette into the cavity. This position combined with aggressive sampling by banging on the wall paneling with a flashlight is more likely to collect problem particles if they are present close to the point of vacuum cassette insertion into the wall. But even this approach is not a reliable characterization of mold risk in the building. And it is not looking into the wall cavity itself - rather we are looking at the two surfaces behind the paneling.
Our photo (left) shows a short-duration but larger surface area or wall opening vacuuming system invented and tested by the author - it did not provide useful results. Longer vacuum pump duration samples for viable sampling (2 hours into an MCE cassette for culturing) still may not move enough air to sample through a cavity, particularly if the cavity is insulated. Further, two-hour samples means that most-likely very few sample points were collected, making the inspection scope extremely limited and thus overall confidence in the accuracy of the picture of the building lower. Consider that the popularly-marketed version of this wall cavity vacuuming approach to test for hidden mold contamination in buildings relies on culture of the sample. Did you know that only about 10% of molds grow in any culture at all? You're 90% uncertain of the accuracy of the test at the outset. One can't be sure that the mold that grew in the culture represents the dominant problem mold or whether it's just a low-occurrence (in the building) spore that liked the media (in the culture). We like cultures for further genera/species identification of samples but we are nervous about relying on them to tell me if the building has a problem or not. Frequently Asked Questions (FAQs) about vacuuming building wall or ceiling cavities to screen for harmful mold, allergens, insects, or other particles... Ask a Question or Search InspectApediaQuestions & answers or comments about using vacuum tests on building cavities to screen for hidden mold or hazardous dust. Ask a Question or Enter Search Terms in the InspectApedia search box just below. Technical Reviewers & ReferencesRelated Topics, found near the top of this page suggest articles closely related to this one.
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